As agricultural headers get larger and manufacturers require higher sickle speeds, the stresses imparted on the sickle assembly knifeback have increased. Standard cold rolled steel materials are used in such sickle bars and typically have a tensile strength less than 160 KSI. Various sickle bar assemblies are shown, for example, in a number of patents including U.S. Pat. Nos. 4,942,728; 5,161,357, and U.S. Patent Publication Number 2010/0050587. The present application is directed toward improvements over the state of the art.